ET ISO TR.5925.2: Fire tests -- Smoke-control door and shutter assemblies -- Part 2: Commentary on test method and the applicability of test conditions and the use of test data in a smoke containment strategy

2006·1.5 MB·English

by  Quality and Standards Authority of Ethiopia (QSAE)

Federal Democratic
Republic of Ethiopia
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ET ISO TR.5925.2 (2006) (English): Fire
tests -- Smoke-control door and shutter
assemblies -- Part 2: Commentary on test
method and the applicability of test
conditions and the use of test data in a
smoke containment strategy

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STANDARD
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Fire tes ts —— Smoke-control door
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and shutter assemblies ——
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(cid:3) Commentary on test method and the
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(cid:3) Identical with ISO/TR 5925-2:2006
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Foreword  

This  Ethiopian  Standard  has  been  prepared  under  the  direction  of  the  Technical  Committee  for  Building  
structures  and  elements  of  building  (TC  (cid:1008)(cid:1005))  and  published  by  the  Ethiopian  Standards  Agency  (ESA).  

The  standard  is  identical  with  ISO(cid:876)(cid:100)(cid:90)(cid:3)(cid:1009)(cid:1013)(cid:1006)(cid:1009)(cid:882)(cid:1006)(cid:855)(cid:1006)(cid:1004)(cid:1004)(cid:1010)  (cid:38)(cid:349)(cid:396)(cid:286)(cid:3)(cid:410)(cid:286)(cid:400)(cid:410)(cid:400)(cid:3)(cid:886)(cid:3)(cid:94)(cid:373)(cid:381)(cid:364)(cid:286)(cid:882)(cid:272)(cid:381)(cid:374)(cid:410)(cid:396)(cid:381)(cid:367)(cid:3)(cid:282)(cid:381)(cid:381)(cid:396)(cid:3)(cid:258)(cid:374)(cid:282)(cid:3)(cid:400)(cid:346)(cid:437)(cid:410)(cid:410)(cid:286)(cid:396)(cid:3)(cid:258)(cid:400)(cid:400)(cid:286)(cid:373)(cid:271)(cid:367)(cid:349)(cid:286)(cid:400)
(cid:3)(cid:886)(cid:3)(cid:87)(cid:258)(cid:396)(cid:410)(cid:3)(cid:1006)(cid:855)(cid:3)(cid:18)(cid:381)(cid:373)(cid:373)(cid:286)(cid:374)(cid:410)(cid:258)(cid:396)(cid:455)(cid:3)(cid:381)(cid:374)(cid:3)(cid:410)(cid:286)(cid:400)(cid:410)(cid:3)(cid:373)(cid:286)(cid:410)(cid:346)(cid:381)(cid:282)(cid:3)(cid:258)(cid:374)(cid:282)(cid:3)(cid:410)(cid:346)(cid:286)(cid:3)(cid:258)(cid:393)(cid:393)(cid:367)(cid:349)(cid:272)(cid:258)(cid:271)(cid:349)(cid:367)(cid:349)(cid:410)(cid:455)(cid:3)(cid:381)(cid:296)(cid:3)(cid:410)(cid:286)(cid:400)(cid:410)(cid:3)(cid:272)(cid:381)(cid:374)(cid:282)(cid:349)(cid:410)(cid:349)(cid:381)(cid:374)(cid:400)(cid:3)(cid:258)(cid:374)(cid:282)(cid:3)(cid:410)(cid:346)(cid:286)(cid:3)(cid:437)(cid:400)(cid:286)(cid:3)(cid:381)(cid:296)(cid:3)(cid:410)(cid:286)(cid:400)(cid:410)(cid:3)(cid:282)(cid:258)(cid:410)(cid:258)(cid:3)(cid:349)(cid:374)(cid:3)
(cid:258)(cid:3)(cid:400)(cid:373)(cid:381)(cid:364)(cid:286)(cid:3)(cid:272)(cid:381)(cid:374)(cid:410)(cid:258)(cid:349)(cid:374)(cid:373)(cid:286)(cid:374)(cid:410)(cid:3)(cid:400)(cid:410)(cid:396)(cid:258)(cid:410)(cid:286)(cid:336)(cid:455)  published  by  (cid:47)(cid:374)(cid:410)(cid:286)(cid:396)(cid:374)(cid:258)(cid:410)(cid:349)(cid:381)(cid:374)(cid:258)(cid:367)(cid:3)(cid:381)(cid:396)(cid:336)(cid:258)(cid:374)(cid:349)(cid:460)(cid:258)(cid:410)(cid:349)(cid:381)(cid:374)(cid:3)(cid:296)(cid:381)(cid:396)  (cid:94)tandards  ((cid:47)(cid:94)(cid:75)).  

For  the  purpose  of  this  Ethiopian  Standard  ,  the  adopted  text  shall  be  modified  as  follows.    
(cid:891)(cid:3)The  phrase  “International  Standard”  shall  be  read  as  “Ethiopian  Standard”;  and    
(cid:891)(cid:3)A  full  stop  (.)  shall  substitute  comma  (,)  as  decimal  marker.
TECHNICAL REPORT (cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:3)(cid:40)(cid:54)(cid:3)ISO/TR 5925-2:20(cid:20)(cid:21)(E)

Fire tests —— Smoke-control door and shutter assemblies ——
Part 2:
Commentary on test method and the applicability of test
conditions and the use of test data in a smoke containment
strategy
1 Scope
This Technical Report provides a commentary that explains the general philosophy and factors on which the
test specified in Part 1 of ISO 5925 has been designed, to describe the limitations of its application and to
provide some general guidance for those who use the result of the test. Smoke control-door and shutter
assemblies can be used as part of a smoke containment strategy for the purposes of life safety or property
protection.
2 Terms and definitions
For the purposes of this document, the terms and definitions given in Part 1 of ISO 5925 and the following
apply.
2.1
door assembly
assembly comprising a fixed part (the door frame), one or more movable parts (the door leaves) and its
hardware
NOTE The purpose of the door assembly is to allow or prevent access of persons and/or goods. The term hardware
includes such items as hinges, latches, door handles, locks, keyholes (excluding keys), letter plates, sliding gear, closing
devices, electrical wiring and any other items that can influence the performance of the assembly being tested.
2.2
shutter assembly
assembly comprising fixed parts, e.g. a barrel housing and vertical guides and one or more moveable parts,
normally in the form of a curtain constructed from linked metal laths, or other flexible material and a barrel on
which the curtain is wound together with any powered mechanism, e.g. an electric motor and its associate
power supply
NOTE The shutter assembly is to allow the passage of goods, vehicles or persons, albeit where the shutter is
normally closed in use, a personnel door should be provided for the passage of persons.
2.3
fire door
door or shutter assembly capable of maintaining for a specified period some, or all of the fire resistance
criteria defined in ISO 3008, as appropriate for the door in use
2.4
smoke control door
door or shutter assembly whose primary function is to restrict the passage of smoke as determined by a test in
accordance with Part 1 of ISO 5925
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(cid:40)(cid:54)(cid:3)ISO/TR 5925-2:20(cid:20)(cid:21)(E)
2.5
fire and smoke control door
door or shutter assembly meeting some, or all of the criteria for fire and smoke control as appropriate for the
door in use
2.6
ambient temperature
for the purpose of this Technical Report, ambient temperature is an air temperature of (20 (cid:114) 10) °C
2.7
medium temperature
for the purpose of this Technical Report, medium temperature is an air temperature of (200 (cid:114) 20) °C
2.8
high temperature
temperature representative of a standardized fully developed fire which is as specified in ISO 834-1
NOTE For ease of use, doors are identified by a code letter/number and these are shown in Figure 1.
2.9
make-up air
air that is made available to dilute the fire gases in order to reduce their temperature
3 General principles
3.1 Smoke and its influence
Smoke is the term used to describe the airborne products of combustion generated by the fire, together with
large volumes of air that become entrained into them due to their motion. These combustion products can
contain solid and liquid particulates within a gaseous mass.
Almost all fires produce smoke, which, when enclosed by a building, has the potential to become extremely
hazardous to its occupants and damaging to property. Most deaths in fires are due to smoke inhalation, rather
than to the victim having been burned.
The gaseous combustion products, chiefly carbon dioxide and water vapour, usually include toxic gases, the
most common being carbon monoxide, although hydrogen cyanide and other minor species can be present to
some extent. Amongst these, irritant gases such as acrolein can have a significant effect on people attempting
to escape fire.
The solid and liquid fractions of the products of combustion are also responsible for the poor visibility through
smoke. This adds to the problems presented by the smoke. Not only is it physiologically hazardous in its own
right, but escape through it is made more difficult by it obscuring escape routes. These fractions can
themselves be irritants and can be particularly dangerous to people who are subject to asthma or other
respiratory problems.
Smoke can also cause damage to property. Most fires produce soot and many generate corrosive gases such
as hydrogen chloride. The effect of these on sensitive equipment can be responsible for large monetary
losses due to equipment damage, the need for system clean-up and subsequent business interruption.
3.2 Smoke dynamics
All fires start from an ignition and grow at a rate generally determined by the environment in which the fire
starts and the nature of the materials involved in the event. Sometimes the fire can smoulder for a
considerable period, especially if the materials that have been ignited have a low rate of heat release or the
environment does not readily sustain combustion. Smoke produced during such a fire has very little buoyancy
and whatever buoyancy it has due to gas density differentials as a result of increased temperature is soon lost.
2 (cid:139)(cid:40)(cid:54)(cid:36)
(cid:40)(cid:54)(cid:3)ISO/TR 5925-2:20(cid:20)(cid:21)(E)
Smoke produced under these low temperature conditions is, therefore, subject to the movement dominated by
the ambient air current, particularly any that is induced by mechanical means, such as ventilation and air
conditioning. In the absence of ambient currents, these cool gases generally mix with the environment and do
not stratify as is expected from hot buoyant gases.
Once the heat release increases, the smoke’’s buoyancy increases and it soon begins to dominate air currents
in the enclosure. When the fire reaches a sufficient size, the smoke rises in a plume towards the ceiling. As it
does so, it entrains large volumes of air, greatly increasing smoke volume but reducing its temperature and
the concentration of chemical constituents.
The total entrained volume of air increases substantially with increasing height of the plume. With sufficient
buoyancy, the smoke impinges the ceiling, spreading out radially to reach any side walls and then forms a
layer that deepens as more smoke is produced.
Smoke flows out of the enclosure of origin through any upper openings that exist or develop. This outflow is
balanced by an inflow of air usually at a lower level. The openings can exist by design or occur as a result of
failure of one of the boundary elements.
An opening can be part of a smoke ventilation or extract system, where either vents open to allow smoke out
or a fan-assisted ducting system exhausts the hot gases and smoke. In such cases, make-up air is required to
come into the enclosure at a lower level, normally from designated sources, but also, possibly, from around
doors. Doors designed to provide make-up air do not require smoke sealing around their perimeter.
Similarly, one of the boundary elements most likely to fail as a result of the exposure to hot gases is windows
in the external façade, where high temperature differentials on the surface of the glass can lead to shattering.
Under ideal environmental conditions, this exhausts the smoke, making the need for enclosure sealing
unnecessary. However, unlike a designed-in vent that is designed to work in conjunction with winds from most
directions, the failure of an external window on a façade with a wind imposed on it can have the opposite
effect. Any wind-induced pressure in the enclosure can impose demands on the walls separating other parts
of the building with respect to their ability to prevent smoke leakage through gaps.
Similarly, if the enclosure is unfenestrated or where the windows do not break as a result of the thermal
exposure, then the pressure increases and the smoke layer deepens.
A normal door is the one element in the boundary of a structure that is naturally leaky, having a gap all around
the moving leaf, unless a seal is introduced to restrict it. A smoke-control door is provided to restrict the flow of
smoke, whether it is wind-induced or the result of natural buoyancy.
It should be recognized, however, that any smoke transferring through door gaps is likely to lose much of its
heat energy in the process and, as a consequence, the temperature and buoyancy are also reduced.
Experimental work has demonstrated that smoke leaving an enclosure via narrow gaps, such as those around
a door leaf perimeter, soon become fully mixed with the air.
Within the enclosure, as new flammable material becomes involved as a result of increasing heat transfer to it,
more air is required for the fuel volatiles to burn. If this is not available, either the fire does not grow any further
or the fuel volatiles burn instead outside the enclosure of origin, i.e. after moving via windows to the open air
or to an adjacent ventilated space, if it is available.
Without engineering intervention, it would be natural for the space containing the fire to contain hot buoyant
gases and for the immediately adjacent, protected spaces to fill with clean air without any buoyancy.
4 Smoke control
4.1 Design objectives
Since smoke can have a major impact on the overall design of the building, it needs to be considered at the
earliest possible stage of the design process. Normal escape provisions in buildings, e.g. restrictions on travel
distances and emergency lighting provisions, do not assume significant levels of smoke management. Where
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(cid:40)(cid:54)(cid:3)ISO/TR 5925-2:20(cid:20)(cid:21)(E)
good smoke management is introduced, either by exhaust, ventilation, pressurization or by containment, then
these provisions may be relaxed. Any such relaxation has a profound influence on the building design/layout
and, therefore, it is important that the method of smoke control to be used be nominated early in the design
process.
Smoke-control systems for life safety are designed to maintain a tenable environment for occupants to
facilitate their safe escape from the building to a place of relative safety or a refuge, preferably separated
structurally from the area being evacuated. Smoke-control systems for property protection are generally
designed to reduce the level of contamination in a space by keeping smoke logging down to acceptable levels.
There are a number of ways that smoke control can be achieved:
(cid:127) natural ventilation;
(cid:127) mechanical smoke exhaust;
(cid:127) pressurization;
(cid:127) smoke containment.
NOTE An alternative to pressurizing a space is to depressurize the adjacent spaces(s), but this is difficult to achieve
in a fire, as the depressurization fans are generally overwhelmed by the fire gases.
The choice of system may be dictated by the area in which the smoke is to be controlled. With such ““active””
measures, then, natural or powered exhaust is more appropriate then ““passive”” smoke containment has a
limited function, and can possibly make the situation worse by lack of the make-up air, and hence reduced
entrainment and higher gas temperatures, as discussed in 4.2, unless separate provision is made for
““make-up”” air.
If, however, it is an adjacent space that is to be protected, then a method that has been used historically to
keep such an area free of smoke has been pressurization of the space, especially staircases. Actively
exhausting smoke from the area on fire also provides some protection to the adjacent spaces. This protection
can be compromised if the smoke temperature in the space exceeds the operating temperature of the fan,
causing it to cease operating. At such times, the space becomes vulnerable to smoke logging.
A simple-to-introduce alternative to exhaust or pressurization is the use of smoke containment, initially
between the enclosure on fire and the space being protected or between adjacent protected areas.
4.2 Protection of adjacent and remote/removed spaces by smoke containment
For smoke containment to work, it is important that the elements bounding the enclosure of fire origin and the
adjacent enclosures remain impermeable to the flow of smoke and hot gases for as long as is necessary to
maintain tenable conditions for life safety or an adequately pollution-free environment for property protection.
There are several fairly distinct stages in this scenario that it is important to address individually for each
space in which smoke is contained.
4.2.1 Scenario within the room of fire origin
In the period immediately following a small ignition, assuming that the materials initially involved in the fire
have a high thermal inertia and a relatively low rate of heat release, the smoke cools and mixes readily with
the surrounding atmosphere. As such, the barrier formed by the bounding structure can initially experience
exposure to cool, ambient smoke. As such, any seals designed to restrict that smoke, including seals around
door edges or the sealing systems used to retain glass within the door leaf, are required to be effective at only
ambient conditions. If the fire continues to grow in intensity and size, with a corresponding increase in the rate
of heat release, then the plume becomes buoyant, increasing in both temperature and volume. The
temperature of this plume becomes elevated and any ambient temperature test method for evaluating smoke
containment can be inappropriate. It is possible by reference to the appropriate scenario in 4.2.2 to 4.2.4 to
produce an estimate of the smoke temperature and hence identify the most suitable test regime to reproduce
those conditions.
4 (cid:139)(cid:40)(cid:54)(cid:36)
(cid:40)(cid:54)(cid:3)ISO/TR 5925-2:20(cid:20)(cid:21)(E)
In addition to the heat release from the fire, there are many other features that influence these temperatures:
(cid:127) height of the room;
(cid:127) thermal losses to, or through, the boundary structure;
(cid:127) availability of make-up air (dilution);
(cid:127) presence of a suppression system.
In a single-storey enclosure, initially these elevated temperatures are imposed only on seals in the upper part
of the enclosure and can be applied to linear-gap seals, glazing seals or service penetration seals for which
no smoke-leakage tests currently exist, neither at ambient, nor elevated temperatures. Seals fitted around the
perimeter of door assemblies are not exposed to smoke at these temperatures until the smoke layer has
deepened to below door head height, although there are a number of gas temperature/buoyancy conditions as
the smoke goes through the transition from smouldering to fully buoyant.
Once the gas layer descends below 2,7 m, especially if it has a temperature of around 200 °C, the
temperature currently recommended in Part 1 of ISO 5925, the conditions are life threatening to the occupants
of the space. If there is a risk of the smoke extending down to this height, then smoke management by
exhaust and/or dilution is normally introduced to ensure that these temperatures and smoke layer heights do
not develop or are not exceeded. It is only in a single-storey environment without smoke management that
doors installed at ground-floor level are subjected to smoke at such temperatures and, even then, probably
only over the upper part of the leaf.
However, doors can be installed at a higher level in such a space, e.g. off a gallery, balcony, a mezzanine or
large unprotected accommodation stair, in which case the doors are subjected to smoke/gas temperatures
greater than this, even before a flashover or full fire development has occurred in the enclosure. Doors in such
locations can experience medium temperature conditions over their full height, including the threshold, at an
early stage in a fire.
Following the full development of the fire, either following flashover or as a result of the free burning of the
adjacent contents in an enclosure that is too large to flashover, a door can be expected to experience
exposure to smoke and hot gases at, or near, fire temperatures. Within Part 1 of ISO 5925, there are no such
conditions specified. In practice, there is no recognized method of quantifying leakage in the fully developed
fire but experimental evidence indicates that intumescent seals, fitted to the leaf perimeter of a doorset, can
be expected to restrict the flow of ““hot”” smoke.
Whilst fire-resisting, smoke-control doorsets do not play a constructive role in a natural, or powered smoke-
exhaust system, vertical-drop steel rolling steel doors/roller shutters can play a useful function in such
applications. As part of a smoke exhaust system, it is important that the buoyant smoke that collects at a high
level in an enclosure is not allowed to traverse too far because the gases would be further diluted and lose
their buoyancy as a result of a loss of their temperature differential compared to the ambient conditions
outside the building. The egress velocity of the gases through vents is governed by the differential
temperature and so this is important. To prevent this dilution and cooling, smoke screens or curtains are used
to create a smoke reservoir, which aids the extraction. Partly dropped roller shutters can be used to act as
smoke curtains or reservoir screens and may be used partially closed, thereby providing a source of input air
for the smoke exhaust system at the bottom, but at the same time providing a barrier to reduce smoke spread
nearer the top.The egress velocity of the gases through vents is governed by the differential temperature and
so this is important.
From the above, it can be seen that doors in the boundary of an enclosure of fire origin are exposed to various
smoke temperatures and over/under pressures, depending upon the level at which they are installed, the
stage in the fire and the smoke-management measures that are incorporated.
Table 1 identifies, for doors in the space of fire origin, the appropriate exposure conditions to consider when
determining the smoke-tightness requirements for the doors in these applications.
(cid:139)(cid:40)(cid:54)(cid:36) 5
(cid:40)(cid:54)(cid:3)ISO/TR 5925-2:20(cid:20)(cid:21)(E)
Table 1 —— Summary of smoke exposure conditions for doors in the boundary
of the space of fire origin
Smoke Door configuration a
temperature A b B c C d D e
Ambient Briefly at the beginning Very briefly over the full Briefly at the beginning No exposure
and possibly over full height of the door and possibly over full
height of door height of the door
Medium For an extended period For an extended period No exposure Extended periods over
up to the onset of up to the onset of full height f
flashover over the upper flashover over the full
2/3rds of the door height of door, including
the threshold
High For the period following For the duration No exposure g No exposure g
flashover and over the between flashover and
majority of the door extinguishment over full
height height
a See Figure 1.
b A: Door assemblies at ground-floor level within the boundary of an enclosure (GF1) without an ““active”” smoke-control system operating in
the enclosure.
c B: Door assemblies at elevated positions within the boundary of an enclosure (E1) without an ““active”” smoke-control system operating in
the enclosure.
d C: Door assemblies at ground-floor level within the boundary of an enclosure (GF1) with a properly designed ““active”” smoke-control
system operating in the enclosure.
e D: Door assemblies at elevated positions within the boundary of the enclosure (E1) with a properly designed smoke-control system
operating in the enclosure.
f The amount of the door subjected to medium temperature smoke depends upon position of neutral pressure axis within the space.
g Can experience these conditions if smoke control system is overwhelmed or fails.
4.2.2 Scenario within a ground-floor space adjacent to the enclosure of fire origin with no active
smoke control in the enclosure
Whilst the boundary to the enclosure of fire origin remains imperforate, the adjacent, protected spaces are not
likely to experience any smoke logging. However, if the door(s) to the fire enclosure (F1) are not sealed
against the flow of smoke or are not fitted with a thermally activated fire seal, e.g. an intumescent seal, smoke
initially percolates around the door edges, especially over the upper 2/3rds (above the neutral axis) and after a
while, as the pressure differential between the spaces increases due to increased volumes of combustion
gases and increased temperatures, the smoke starts to flow readily into the protected space through any gaps.
Experimental work has shown[1] that small confined adjacent single-storey spaces on the ground-floor, such
as corridors, smoke log quickly as a result of this leakage if the doors (and walls) are not effectively sealed.
Even if the door to the fire enclosure is fitted with a smoke seal, unless the seal has a resistance to high
temperatures, it breaks down as the temperature increases in the fire compartment/enclosure and once more
allows smoke and combustion gases to flow through unimpeded. Experimental evidence has also
demonstrated that, even when the smoke seal fails due to the temperature of the gases imposed on the seal
on the fire exposed side, these gases cool significantly as they lose energy to the surroundings and initially
have a temperature that is only slightly, if at all, above ambient. During this period the adjacent space is filling
with ““ambient”” temperature smoke.
If heat-activated (intumescent) seals are fitted, then this smoke flow can be significantly reduced in volume
and its temperature remains at ambient levels.
If no heat-activated seals are fitted, then the temperature of the gases passing through the assembly gradually
increase and the gases in the protected space start to become buoyant. The temperature of the air/smoke in
6 (cid:139)(cid:40)(cid:54)(cid:36)